Healthy-weight toddlers protected from later obesity

Prevent obesity in the under-5 and the benefits can last years. This was the message of a widely reported study published this week. So how do you help youngsters maintain a healthy weight?

The new study involved 7700 children and was led by Solveig Cunningham of Emory University in Atlanta, Georgia. Her team showed that if children reach their fifth birthday without becoming overweight or obese, their chances of developing obesity as a teenager are reduced fourfold. The researchers conclude that obesity might be best tackled by focusing on measures to prevent it in the pre-school years (NEJM, doi.org/q9n).

Perhaps the first place to begin tackling childhood obesity is before the child is even born. Studies suggest that taking action to correct poor lifestyle choices and poor diet in mothers – both before and during pregnancy – could affect the fetus and decrease the resulting child’s subsequent vulnerability to obesity.

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For instance, a study led by Julie Dodd at the University of Adelaide in South Australia showed that dietary management of pregnant women who were themselves obese – a risk factor for having overweight babies – reduced by 14 per cent the likelihood that their babies would be heavier than 4 kilograms (9 pounds) – a weight that, in Australia, puts a baby among the heaviest 10 per cent.

“Genetics plays a role, as does epigenetics – the programming of genes in the fetus,” says Elsie Taveras of the Massachusetts General Hospital in Boston, who co-authored an editorial in the NEJM commenting on Cunningham’s results this week. “The fetal environment may therefore have impacts which predispose the baby to be especially vulnerable to rapid weight gain.”

Resetting expectations

After the birth, focus might shift to the quality – and quantity – of a baby’s diet. Here, reducing the protein content of infant formula so that it matches that of breast milk is proving effective. A 2009 study led by Bert Koletzko of the University of Munich Medical Centre in Germany showed that babies grew just as long but were 20 per cent lighter if fed on low-protein rather than high-protein formula. They also matched the weight-gain patterns of breastfed babies more closely. “It’s cheap and easy, and all it takes is changing the recipe,” says Koletzko.

Meanwhile, Ken Ong at the University of Cambridge is leading a study to give behavioural support to mothers whose babies are growing exceptionally fast through overfeeding. The idea is to try to help them bring their babies to more normal rates of growth.

“It’s not just telling mothers how much to feed, but re-setting their expectations about what’s healthy growth,” says Ong, who has so far recruited 400 of the target 700 mothers he needs to begin the study.

Historical hangover

Historically, says Ong, one of the problems has been that fast weight gain has been seen as a good thing. This was not helped by earlier birth growth charts, which actually encouraged overfeeding. Based on formula-fed babies, the charts have now been replaced by the World Health Organization to reflect healthy weights calibrated by breastfed babies.

It’s not all about diet, though&colon; the environment around a baby or young child is a factor too, says Taveras. Trying to introduce regular sleep patterns and avoiding exposure to fast-food advertising on television can help.

“We published a study in September showing that introduction of healthy routines to households at risk had a significant impact within six months,” says Taveras. “Body mass indexes were half a unit lower in the intervention group than in the control group. This is large enough to make the difference between being classed as obese or overweight, or between being overweight and normal weight.”

The good news is that these strategies appear to be bearing fruit&colon; rates of childhood obesity in the US and elsewhere in the world are showing signs of falling.